She was only doing the event for a bit of fun, got spiked and fell in the heats, only got into the semi-finals after a protest yet Jessica Hull has broken the Australian 800m record in the semi-finals.

There’s nothing Australia’s middle-distance iron woman can’t do with Hull, who was backing up from winning a bronze medal in the 1500m on Tuesday night, producing a massive career-best 1min57.15sec to finish third in her semi-final.

The time was 0.52sec under teammate Claudia Hollingsworth’s mark which she only set last month. Ironically, Hull’s record-breaking performance knocked Hollingsworth out of Sunday’s final.

Only the first two placegetters in each semi-final are automatic qualifiers then it’s the next two fastest.

Hollingsworth, 20, finished fourth in the opening heat (1:59.50sec), so she was still alive before Hull’s heroics in the second semi-final.

Hull suffered a major gash to her leg when she was spiked and fell during Thursday’s heats and protested immediately. She was reinstated into the semi-final field by race judges an hour later.

“I’ve known that time was in there since about April when I ran 1:58 in Jamaica and we hadn’t done a tonne of 800 specific work,” Hull said.

“I kind of then thought I could really get something like that out there.

“This championship has been quite dramatic by my own standards (with the fall) so I just put my head down and went to work tonight, and I’ve got 48 hours to recover for the final.”

National champion Abbey Caldwell also didn’t get through, finishing fifth (1:58.44sec) in the third semi-final.

Another proven performer to lift for the big occasion was javelin thrower Mackenzie Little.

Before she flew out to Tokyo the Sydney doctor worked three night shifts in the emergency department of the Royal North Shore Hospital and one of her lost jobs was to save a man who’d suffered a massive heart-attack.

On Friday night Little gave her opponents an early heart murmur when she made a stunning statement at the start of the javelin throw qualifying.

Little produced a massive season’s best 65.54m with her first throw which was well over the 62.50m automatic qualifying mark.

“The season has been up and down, it’s been really hard. more so than ever,” Little said. “Dragging myself to training after a long day’s work.

“Don’t want to say that I want it to be worth it, but I just want to enjoy this. I threw that throw and it was light, easy, fantastic and it just felt so good.

“I then turned around, looked at my coach and it was like ‘thank you’. We’ve had to work really hard and it’s kind of coming together.”

A brilliant tactical run from Ky Robinson got the Australian a berth in Sunday’s 500m final.

Robinson, 23, was at the front of the pack for the entire race and cruised to the line to finish fifth – the top eight were automatic qualifiers – in 13min13.60sec.

He is seeking to emulate Craig Mottram who won Australia’s only medal in the event, a bronze in Helsinki in 2005.

Unfortunately Melbourne’s Seth O’Donnell struggled in his major championships debut (13:34.52sec) while in the second heat Jack Rayner finished 16th (13:49.46sec).

Olympic champion Jakob Ingebrigtsen, who has had an injury-interrupted season, fell into the final qualifying spot in the second heat to keep his chances alive of a third consecutive world 5000m title.